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fastmcp.server.providers.prefab_synthesis

On-demand Prefab renderer resource synthesis. Tools marked as Prefab (via app=True, PrefabAppConfig, etc.) carry a placeholder meta.ui.resourceUri and optionally a hash in meta.fastmcp.tool_hash. This module synthesizes per-tool renderer resources on demand at list_resources and read_resource time without storing or materializing anything. Each tool’s resource URI is ui://prefab/tool/<hash>/renderer.html where the hash comes from the tool’s own meta (set at registration from the app name + tool name). CSP on the resource is the tool’s meta.ui.csp merged with the renderer defaults across all four *_domains fields.

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Functions

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synthesize_prefab_resources

Return fresh synthetic Prefab resources for all prefab tools. Pure.

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synthesize_prefab_resource_by_uri

Intercept a Prefab renderer URI and synthesize on demand.

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rewrite_tool_meta_for_wire

Return a model_copy with the per-tool URI and CSP stripped. Reads the hash from the tool’s own meta. If no hash is found, returns the tool unchanged. Produces a fresh copy — the original Tool object is untouched.